The present invention relates generally to differential drivers, and more particularly to a differential voltage mode driver.
Differential drivers are used in many data communications applications. Many of these applications demand high data transfer rates, including for example, video, integrated circuit (IC), and Ethernet applications. For integrated circuits, differential drivers often provide communications between circuits on an IC chip and between the IC chip and a circuit board. In Ethernet applications, differential drivers can be used for high speed communication applications such as 10 gigabit Ethernet or other Ethernet standards. In one implementation of 10 gigabit Ethernet, sometimes referred to as CX4 or IEEE 802.3ak, data is transmitted bi-directionally over four data lanes using copper cabling. Each data lane can be responsible for 3.125 gigabaud of data transport.
Differential drivers operated at high speeds may face varied circumstances. In many cases, it may be difficult for differential drivers to drive outputs at high speed. In addition, in systems capable of high speed operation, differential drivers may need to support a wide range of low amplitude swings and high amplitude swings. Further, differential drivers can have difficulty in operating with reduced power consumption at high speed. For example, differential drivers often need to be efficient when driving both low and high amplitude swings to minimize power consumption. Such difficulty can be magnified if accounting for impedance matching. Further, operation of the differential driver may change or vary due to process, voltage, and temperature variations.